Faculty Bibliography

Deep hypothermic circulatory arrest has become an essential technique to allow repair of complex congenital cardiac lesions in children. The arrested state has concerned the surgeon, cardiologist, and anesthesiologist alike, and yet deep hypothermic circulatory arrest has been highly successful with a low incidence of neurologic sequelae. Studies of cerebral blood flow and cerebral oxygenation demonstrate that the arrest hypothermic brain does not develop the immediate postarrest hyperemia or hyperoxia seen in normothermic ischemic brain models. However, both hypothermic and normothermic ischemic brains exhibit hypoperfusion beyond the immediate recirculation period, likely coupled with a reduced cerebral metabolic rate. That the hypothermic arrested brain likely becomes anoxic and recovery of the anoxic brain depends in large part on recirculatory hemodynamics suggests that the lack of hyperemia and hyperoxia may play more major roles than was previously believed. The mechanism of protection may be related to suppression of oxygen free radicals

Ocular ultraviolet radiation (UVR) exposure was assessed in three occupational groups: fisherman, landscape workers and construction workers. The ratio of ocular exposure to ambient exposure was determined by placing UV-sensitive film (295-320 nm) between the eyes of the subjects and in a nearby open field. The mean ocular exposures varied between 2 and 17% of the ambient exposure on a horizontal surface, depending on whether subjects wore hats, the job performed and the time of year. Wearing a brimmed hat significantly reduced ocular exposure in all groups of subjects. Subjects working over more reflective surfaces had significantly higher ocular exposure. A seasonal effect on the ocular ambient exposure ratio (OAER) was also observed. These results are consistent with measurements of OAER in mannikin and measurements of surface reflectivity in this and previous studies. The results provide parameters which can be used in modeling ocular UVR exposure in epidemiological and clinical studies